When applying for a UK visa, how old should the bank statement be?
The guidance says they should not be more than a year old. Ideally, you'll show several months of statements, so by definition most of them will be more than a month old.
Section 4: documents you should not send unless specifically requested
This page provides guidance on the types of documents that are not required to consider your application.
if you are applying as a family/group you do not need to provide multiple copies of the same documents
bank statements or letters issued more than 1 year before the date of application